Historic
Wallpaper Conservation

Phillipa
Mapes

Detail of an early 18th century 'Gothick' style wallpaper,
hand-
blocked
using distemper colours.

Decorative
finishes have as great an impact on the character of an interior
as any architectural element or material. Wallpapers in particular
are among the most significant, not only because of the visual impact
of their design, their colour and their finish but also because
of the high proportion of the surface area of the interior which
may be affected. Today historic wallpapers are also attracting increasing
interest as art and design objects in their own right. However,
they are among the most vulnerable elements of a building, subject
to changing patterns of taste, accidental damage, and decay, and
within the historic interior surviving examples are rare, placing
even greater importance on their conservation and understanding.

The
conservation of historic wallpapers relies on the skills of the
trained paper conservator. As an element of the historic interior,
their conservation must necessarily draw on the skills of easel
painting, wall painting and textile conservators also, and as an
element of the fabric of the building it may also involve close
liaison with architects, historic building advisers and other specialists,
particularly where deterioration is concerned.

Aside
from this multi-disciplinary approach, the conservator must also
be able to recognise period designs and styles which not only encourage
appreciation, but also help identify contemporary materials and
manufacturing techniques. These in turn have a bearing on the choice
of conservation treatment.

HISTORICAL
BACKGROUND

The
earliest known wallpaper in Britain is thought to date from 1509
and was found covering the beams of the Dining Hall at Christ's
College, Cambridge. The wallpaper had been printed by carved wooden
block in monochrome on the reverse of single sheet documents. These
early papers were usually handmade from reconstituted rags; small
sheets were pasted together along an edge to make up a length, and
then printed by wood block or stencil (or a combination of the two),
using distemper or oil based colours. This type of production became
the norm for wallpapers until industrialisation in the 19th century.

Wallpaper
at this time provided a less expensive alternative to textile hangings.
As such, designs imitated contemporary textile fashions. Flock wallpapers,
made by sprinkling chopped wool over a design printed in adhesive,
were deliberate reproductions of the damasks and cut velvet wall
hangings of the day. Despite their rather ignoble reputation today,
flock wallpapers were expensive, prestigious items and like most
wallpapers were popular with the wealthy, fashionable classes.

Wallpaper,
on either Oriental paper or silk, was also imported from China.
These were exquisitely hand-painted to depict stylised gardens of
flowers, trees and birds, or scenes of traditional daily life in
China. Due to their beauty and fineness of execution, these papers
became commonplace in the majority of stately homes in Britain during
the 18th and into the 19th centuries and still accounts for their
survival today.

By
the mid 19th century, wallpaper production joined in the industrial
revolution. Increasing demand for paper was met by the use of wood
pulp, which was quickly and cheaply processed, but initially resulted
in a poor quality, acidic paper. Developments in the papermaking
machine allowed continuous lengths of paper to be produced. These
in turn could be printed using new mechanised wooden and metal rollers.
Concurrent developments in colour production also provided possibilities
for new and more varied colours, including some 19th century experiments
with arsenic green.

Alongside
the rush for mechanisation, some manufacturers were still producing
handblocked wallpaper including the doyen of the Arts and Crafts
Movement, William Morris, who issued his first wallpaper in 1864.
Competition was also strong from the UK's customary rivals, the
French, who were producing incredibly elaborate scenic wallpapers
for a very appreciative British market. These large 'panoramiques'
usually consisted of non-repeating landscapes or vistas which continued
around the room and could necessitate cutting over 1,000 blocks
in order to print the different elements of the design.

Innovations
continued to keep up with, and create demand for new types and designs
of wallpapers. By the end of the 19th century, embossed wallpapers
such as Lincrusta Walton had become popular, and special, damp-resistant
wallpapers were being produced specifically for bathrooms and kitchens
with the development of 'sanitaries', which were machine printed
in oils and varnished.

Although
the industrialisation of the wallpaper industry is often associated
with the introduction of poor quality materials and designs, many
fine examples were produced and can still be seen today. It should
also be noted that increased production provided the opportunity
for all but the very poorest levels of society to afford and enjoy
wallpaper, and to take pride in the decoration of their homes.

DETERIORATION
OF HISTORIC WALLPAPERS

To
highlight the principal types of deterioration effecting historic
wallpapers in situ, causes can be broadly divided into 'external'
and 'inherent' factors.

EXTERNAL
FACTORS

As
with all works of art on paper, historic wallpapers are susceptible
to damage by exposure to light and fluctuations in temperature and
relative humidity. Combined with the effects of atmospheric pollutants,
these can cause the breakdown of the paint layer and the paper support.
Further problems can also occur as a result of the differing responses
of the various laminations of the decorative surfaces and its substrate
to environmental conditions, and wallpaper conservation should not
be regarded as the treatment of the wallpaper alone. The wallpaper,
adhesives, linings, canvas, plaster laths and other elements may
each respond differently to variations in temperature and moisture
for example, and varying dimensional movements are often at the
expense of the weakest layer - the wallpaper. Such conditions are
magnified within historic buildings where their wallpapers have
endured seasonal changes, lighting and heating by candle, oil and
coal fires, as well as the installation of central heating systems
and a reduction in ventilation.

Historic
wallpapers are also prone to damage from structural problems of
the building itself. Movement or settlement cracks in walls will
strain and tear the wallpaper at the surface, whilst leaks and damp
spots can cause staining, encourage mould growth and the physical
weakening of the paper, pigments and adhesives. Wallpapers stuck
directly to plaster walls, with or without a liner, may also suffer
disturbance from crumbling plaster or soluble salts emanating from
the wall.

Wallpapers
which have been traditionally hung on canvas and stretchers may
be protected from the above to some extent. However, it is not uncommon
for wooden stretchers to warp and/or the canvas to degrade to a
weak, sagging and acidic carrier for the wallpaper. Traditional
hanging techniques may also effect the longevity of a wallpaper
in their use of impermanent materials, such as iron nails or inferior
quality lining papers and adhesives.

Finally,
more apparent damage to historic wallpapers comes from general wear
and tear, such as human traffic, graffiti, furniture scratches,
and holes made for fixtures among other factors. Although this type
of damage is more obvious, it is usually less serious due to its
localised nature.

INHERENT
FACTORS

Factors effecting the survival of a wallpaper are often directly
attributable to the materials and method of manufacture of both
the paper and the media (paint or ink for example) in which the
wallpaper design is printed. Deterioration and embrittlement of
a paper support dating after the 1850s, for example, could be as
a direct result of the poorer quality paper stock used at that time.
Alternatively, an 18th century Chinese wallpaper may have become
brittle, not because it is of poor quality, but because its thin
laminate construction makes it particularly vulnerable to environmental
changes.

Similarly,
of the wide variety of pigments and media used in historic wallpapers,
many cause damage to the support, or are prone to deterioration
themselves. Starch and animal glue/gelatin binders not only provide
nutrients for insects, but are also prone to desiccation and shrinkage.
This results in powdering, flaking and eventual loss of the pigment
layer. Often design priorities are in conflict with the requirements
of longevity; a matt paint for example, is often deliberately created
using granular pigments in very little binder, but results in vulnerable,
ill-bound paint layers. The conservator must try to preserve this
matt appearance by not saturating the pigments yet at the same time
securely reattaching and consolidating the flaking layers.

CONSERVATION
TREATMENTS

Any
treatment of an historic wallpaper has to take into account several
related factors; the wallpaper, its hanging system, and the architectural
features and environmental conditions of the room itself. Thought
must be given to solving the one problem without compromising the
historical integrity of the whole room. In general, conservation
treatments fall into one of two categories, depending on type and
severity: in situ treatments (which are carried out on site); and
those which involve the removal and re-hanging of the wallpaper.

In
situ treatment is useful where damage is minor and localised, for
example, a tear or small detached area. Surface treatments are often
carried out in situ, such as the removal of non-ingrained dirt or
dust and the consolidation of some types of loose paint media. Deposits
and stains can also often be removed by localised aqueous treatments.

As
in situ work involves treatment of the surface of the wallpaper
only, it is not likely to be appropriate for seriously damaged or
delaminated wallpapers. Its principal disadvantages are that it
does not allow access to the wallpaper support or the wall for investigation
and precludes work to it. In situ treatment is useful however, not
only for cleaning and first aid repair, but providing an overall
survey of the wallpaper in its original position. This can be documented
to aid physical and environmental monitoring, and provide recommendations
for future treatments.

REMOVAL
AND RE-HANGING

Removal
and re-hanging are the most interventive treatments open to the conservator,
and only take place if wall or wallpaper are severely deteriorated.
In order minimise disturbance to the historical integrity of the
wallpaper, it is removed in as large sections as possible rather
than breaking it down into individual lengths.

A
badly water-stained mid 19th century machine-made wallpaper
before conservation

When
hung on canvas, whole walls of wallpaper can be removed by releasing
the canvas from the nails and taking the wallpaper down using the
canvas as a carrier support. Other methods involve dry, physical
techniques using spatulas and blunt knives to work behind the wallpaper.
Alternatively, wet, chemical techniques are used involving a variety
of aqueous solutions and sprays, plus the use of superheated steam
and/or enzymes to break down the adhesive bond between paper and
wall.

Removal
then allows treatment of both the front and back of the wallpaper.
It also facilitates more effective aqueous cleaning, consolidation
and repair techniques and allows for the removal and replacement
of degraded and damaging linings. The wall surface itself can also
be repaired and prepared with a new but historically accurate lining
system on which to re-hang the conserved wallpaper.

The
wallpaper conservator is therefore armed with several treatment
options with which to conserve historic wallpapers. As wallpapers
are viewed as art objects which are part of another historic structure,
consideration must be given to the historic structure as a whole.
The conservator's main priority is the preservation of the wallpaper,
yet acknowledgement of where and how it was hung is also important.
Original methods of production and hanging are replicated wherever
possible. However, where appropriate, modern conservation-quality
materials are used which will protect rather than cause damage to
the wallpaper and help preserve it for the future.

This
article is reproduced from The Building Conservation Directory, 1997

Author

PHILLIPA
MAPES BA HND Con MA Historic Wallpaper Cons (RCA/V&A) is
a partner in the business of Sandiford and Mapes, specialising in
the conservation of historic wallpapers and large works of art on
paper. She has recently produced a temporary exhibition at the Victoria
& Albert Museum, examining the conservation of historic wallpapers,
and has won a Conservation Unit Award for work on Chinese wallpaper.